Durability Evaluation Of Highway Concrete Based On Fuzzy Theory

Concrete has been regarded as a durable material for a long time.However,the fact is that the concrete structural damage has mostly arisen because of the durability degradation after structures came into service.Compared with the general building,the service environment of highway is even worse,and the highway bears the vehicle load.Including highways,many concrete structures have been destroyed before the design life because of the coupling of various degraded factors.The loss caused by durability damage is enormous,which makes people pay more attention to the durability of concrete structures.The durability evaluation of highway concrete was studied in this paper,and a method of fuzzy evaluation for durability of highway concrete which based on the life-cycle theory was proposed,and this method was verified by an engineering example.This thesis studied the following aspects:1.The causes of deterioration of concrete structural durability were concluded.Combined with the technical characteristics of highway,the influences of deterioration factors on the durability of highway concrete were analyzed.2.Some methods of evaluation were described.This paper especially introduced the fuzzy comprehensive evaluation method,and then introduced the steps and deficiencies of this method.For the deficiencies,life-cycle theory was introduced,and the factors that affect the durability of concrete structures can be divided into two aspects: the promotion and the recession.Based on life-cycle theory,the durability method of fuzzy evaluation was proposed.3.According to the factors of promotion and recession,the index system for durability evaluation of highway concrete structures was established,and the standards of classification of indexes were determined by specifications and related research results.In addition,this paper introduced the Analytic Network Process when the factors weight were divided.4.Based on the fuzzy evaluation method,which was proposed in this paper,an actual project was evaluated and analyzed.The effectiveness of the method was validated by the comparing of calculated results and the actual situation.A set of durability fuzzy evaluated system of highway concrete structures that based on the life-cycle theory which was established in this paper,and the researches of concrete structures durability evaluation were further improved and supplemented,the evaluation of durability aims to provide the theoretical basis for maintenance and reinforcement of structure.Meanwhile,the results of evaluation can be fed back to the design,construction and other departments,and the experiences of engineering can be accumulated and summarized.Simultaneously,this method can also be applied to the durability evaluation of other concrete structures.